Self-synchronous automatic pilot



Sept. 24, 1935. 5 HODGMAN I 2,015,183

SELF SYNCHRONOUS AUTOMATIC PILOT Filed Oct. 27, 1931 4 Sheets-Sheet lGYRO i COMP/13S ll! //2 a //0 me e 8 INVENTOR Sept. 24, 1935. F, SHODGMAN 2,015,183

SELF SYNCHRONOUS AUTOMATIC PILOT Fiied Oct. 27, 1931 4 Sheets-Sheet 2IIIIIIIIHZZ Sept. 24, 1935. F s, HODG N 2,015,183

SELF SYNCHRONOUS AUTOMATIC PILOT Filed Oct. 27, 1931 4 Sheets-Sheet 4INVENTOR fiPEDER/GK 5J7 DEM/W.

.142 ATTORNEY Patented Sept. 24, 1935 UNITED STATES PATENT OFFICE2,015,133 SELF-SYNCHRONOUS AUTOMATIC PILOT Application October 27, 1931,Serial No. 571,475

7 Claims.

This invention relates to improvements in automatic steering devices forships wherein the course controller is automatically maintainedselfsynchronous with the gyro compass. In the present automatic steeringdevices the controller is geared up to rotate many times for onerotation of the compass or ship in order to obtain accurate control. Incase, howeventhere is a temporary circuit interruption between thecontroller l0 and compass, or in case the controller is turned faster byhand than the ship can follow, synchronism may be lost and may only hereestablished by hand setting, if the ships heading becomes displacedmore than about on either side of the indicated course. According to mypresent system, the controller is made selfsynchronous so that no matterin what relative positions the controller and compass are at the timethe circuit is thrown in, automatic synchronization is established andthe rudder brought to the proper position to steer the ship on thepredetermined course. My self-synchronous system, of course, has broaderapplication than to the steering of ships and is adapted for anyselisynchronous remote control system of a power motor. According to myinvention, I prefer to insert an auxiliary controller or controllers anda small sensitive power motor between the compass controlled repeatermotors and the main 3O steering motor. By this means a much quicker andsensitive control of the ship is obtained for the reasons outlined in myprior application Serial No. 529,939 filed April 14, 1931 for Sensitivere mote control system and automatic pilot. Referring to the drawings,

- Fig. 1 shows in diagrammatic form mysystein as applied to automaticsteering for ships.

Fig. 2 is an elementary wiring diagram of the same. 40 Fig. 3 is adetailed plan View of the cam switches used to operate the main steeringmotor.

Fig. 3-A is a side elevation of the same.

Fig. 4 is a section taken approximately on line c t of Fig. 3-A.

45 Fig. 5 is a vertical section through the primamr Fig. 10 is a wiringdiagram of a modified form of control for the steering motor.

In Fig. 2 the sending instrument, in this case a master compass, isrepresented at i and as usual in self-synchronous remote control systemsthe 5 compass is provided with a course transmitter 2 connected at a lto 1 speed to the compass, and a fine transmitter 3 connected atmultiple speed, such as a 36 to 1 to the compass. The course transmitterdrives the coarse repeater motor l 1 and the line transmitter drives thefine repeater motor 5 at the controller. Each motor may be provided witha repeater card 6 and 'l if desired (Fig. 1). The motors andtransmitters are preferably of the alternating current self- 35synchronous type (see Fig. 2) wherein the fields are continuouslyexcited from an A. C. source S and the armatures are electricallyconnected.

It is well known that such motors are accurate only when little or noload is placed thereon. 20 Therefore, I mount the power motor controlcontacts directly on the shaft of the motor. Also, instead of employingonlya contactor on the fine motor, I prefer one on each motor in orderto secure self-synchronisni as hereinafter described. 25 The coursemotor carries the trolley arm and the fine motor the trolley arm 9, botharms being shown as having a trolley at each end. lhe fine controllermay be of the usual form in which two trolleys bear respectively onupper ring ill and lower slip ring ll, (Figs. 8 and 9). Said rings areshown in Fig. 2 as of different diameter for the sake of clearness. Theupper ring is divided into two parts lll-l(l' by narrow strips ofinsulation and a lead-in brush it bears on the slip ring i i to leadcurrent into the trolleys. If, there fore, the trolleys in Fig. 2 areturned clockwise detail in Figs. 8 and 9 and hereinafter described.

If, on the other hand, trolleys are rotated so counter-cloclcwisa thecircuit is completed through the segment to the other field winding itof the motor, thus driving the motor in the opposite direction.

The motor he made of suincient size 5 to turn the rudder directly orthrough an auxiliary steering engine, but I prefer to make the motor l5very small so as to respond very quickly to the controller and to usesaid motor only to operate additional cam-operated contacts 48- 4|42,which in turn control the main steering motor 43, and to place a lostmotion device between said motor and its controller as hereinafterdescribed.

Except forthis feature the system so far described is quite similar tothe systemslat present in use; but without a connection from the coarseor self-synchronous motor 4 the device would not be completelyself-synchronous. I, therefore, also provide the controller 8 on motor 4with means for causing the same to assume control of motor l5 when theship is off course more than the angle of self-synchronism of controller9, which, with a 36:1 ratio, would be about 5". In order to effect thispurpose, the lead-in current to the trolley 9 is led first to thetrolley arm 8 and from thence, in order to reach the trolley 9, currentmust pass from the lower trolley 8 through the short contact segment 25and thence through the annular external slip ring 26 connected tosegment 25 and thence through the brush 21 to the trolley arm 9 (foractual construction see Figs. 8 and 9). It will be seen, however, thatif the trolley 8 is rotated either to'the right or left through an anglegreater than the width of the segment 25, the current to the trolley 8will be interrupted and the fine controller rendered inoperative. Underthese conditions, however, the upper trolley 8" is moved off theinsulated sector 3| which is of about the same angular width as 25,bringing 8" into contact with one of the live segments 29 or 30 whichare connected through the slip rings 29' and 30' (Fig. 9) and brushes l2and I3 to said field windings l4 and I6 respectively. Therefore, whenthe ship is off its course by an angle sufficient to move the trolley 8"oil the insulated segment 3| and the trolley 8' off the correspondinglive segment 25, the coarse controller operates the motor to bring theship around to within the predetermined degree of synchronism, i. e.,within the limits of self-syn chronism of the fine controller. At thispoint, however, the coarse controller becomes inoperative by engagementof the trolley 8" with the dead section 8| and the fine controllerbecomes operative so that the fine controller alone will bring the shipon to exactly the right course.

There is, of course, provided a follow-back connection between the motorI5 and the controller contacts. The gear connections arediagrammatically shown in Fig. 1. Motor I5 is shown as connected todouble reduction gearing 50- to a shaft 5| on which is mounted a gear 58turning a gear 59 on shaft 60. In this shaft is interposed a lost motiondevice 6| for the purpose, among others, of eliminating the yaw of theship. This device is shown as consisting of a sleeve 62 (see Fig. '7having a pair of triangular slots 63 and 64 therein. The shaft 60 has apin 65 thereon engaging slot 64, while a complementary shaft 56 has apin 61 engaging slot I53. Sleeve 62, therefore, furnishes a looseadjustable lost motion connection between the shafts 6|] and 66, theamount of lost motion being varied by adjusting the sleevelongitudinally on the shafts. This adjustment, as shown, is effectedfrom a pinion 68, the teeth of which mesh with annular rack teeth 89 onthe exterior of the sleeve, the pinion being adjustable from a knob 10in accordance with the readings of cooperating pointer and scale 1|.

The shaft 58 is shown as driving a cross shaft 12 through spiral gearing13. Said cross shaft is shown as geared through one-to-one spiralgearing" to turn the contact rings III of the fine transmitter. Theshaft 12 at its other end drives corresponding contact rings 28-49 ofthe coarse transmitter through suitable reduction worm gearing 15.

Shaft 5| also drives one arm 520i a differential gear train 53. Thecentral or planetary arm of 10 said train is shown as revolved from aworm 54 turning a wormwheel 55 thereon. Said worm in turn is adjustedfrom the handwheel 56 by which course changes or corrections areintroduced in the usual manner. 15

As above indicated I prefer to make the motor I5 very light so as toquickly respond to the controller on the repeater motors to actuate themain contacts for the main motor 43. The lost motion device abovedescribed cooperates to this 20 end by causing motor Hi to turn througha large initial. angle whenever it is first started, thus always closingthe contacts on the main controller for a very small deviation of theship (on the order of 5 minutes or less). For this pur- 25 pose thethird arm 51 of the differential drives one arm 16 of the seconddifferential 11 through gears 90, 90. The second arm 19 is driven from afollow-back repeater motor 18 actuated from a transmitter connected withthe motor 43 to 30 furnish a follow-back connection from motor 43 to themain controller. A hand synchronizing knob 18' may be employed if themotor is not of the self-synchronous type. As shown, the repeater motor18 is connected through gearing 8| to a 35 worm B2 driving a wormwheel83 forming a planetary arm of the gear train. The third arm of saidtrain rotates a shaft 84 which rotates through suitable gearing 85 aplurality of cams 86-81--88 which operate the switches to control 40 themotor. As shown, the cam 86 'has a one-toone connection to the shaft 84while the other two cams are driven through a step-down gearing 89-98-9|so as to be rotated, say, at 1 to 18 speed. Cam 86, therefore, controlsthe fine con- 45 tacts 40--40' (Fig. 2) while the other two cams controlthe coarse contacts 4 I, 42 and 42'. These contacts and motor 43 arepreferably placed on the ship's main D. 0. power circuit represented atP, while the motor |5 maybe actuated from 50 the lighter single phasecircuit used to operate the repeater system of the compass andcontroller.

The fast and slow cam contacts may control the motor synchronously in amanner similar to the 55 commutator'contacts above described. Thusnormally the fast contacts 40 and 40' are in control of the motor, thecircuit to the same being closed by the switch 4|, the roller of saidswitch resting on the raised portion 81 of the cam 81. In case, 60however, synchronism is lost, the roller of contact 4| will ride down onthe lower portion of the cam 81 thus breaking the circuit to thecontacts 40- 40'. At the same time one of contacts 42-42 will be made tooperate the motor from the slow 5 or self-synchronous cam 88. Inthiscase the -motor is shown as having a double wound armature with twocommutators 43'--43" instead of a double wound field as in motor l5,although it is obvious that either form of winding may be 7 employed ineither case. The field 9| is shown as excited directly from the line. 92and 93 are limit switches designed to be open when the rudder Rapproaches the limit of its movement in either direction. The rudder isshown diagram- 75 matically as turned from a rack bar I00 which isreciprocated by the rotation of pinion IOI on shaft I02. There is alsoshown an electro-magnetic' clutch 94 between shaft I02 and the shaft I03of motor 43. Said clutch remains closed only while the electric circuitto the servo motor is closed but which is disengaged when this circuitis broken, thus freeing the rudderfrom the load of the motor 43 when itis desired to steer by hand.

In Fig. 1 motor 43 is shown as driving the rudder R through the usualtelemotoit system, the motor being coupled to the main steering wheel 95through gear box 96', sprocket and chain 96, and clutch 94, thehandwheel operating the rudder through the telemotor or straighthydraulic servo-motor system represented generally at 9'! and 98.

Fig. 10 shows a simplified wiring diagram of the control of the powermotor 43 only. In this case the cam driven contacts 4!); 40', 4!, 42,42' reverse the motor through auxiliary relay contacts 99, 99', I00, ma"operated from windings NH and H12 in circuit with cam contacts. In thiscase the motor is reversed by reversing the current through the armaturewhile leaving the current through the shunt field Hi3 and series fieldma unchanged. Dynamic breaking may be pro vided, if desired, by contactsM5, M15, resistance l0! and coil Hi6 operating switch Hill.

I also prefer to provide at the controller an indication of the ruddermovements as well as of the ship movements so that the pilot may observepromptly whether the helm has moved in response to the controller andalso whether the ship is following the helm properly. For this purpose Ihave shown an upper dial Hill which may be the shape of the ships hulland is driven from shaft its of gear it, the movements of this shaftrepresenting the differential of the compass movements and the handwheel5% so that the dial its constitutes a course change indicator when readon the stationary index Mil. Beneath the indicator its is a rotary dialill having index M2 thereon representing the position of the rudder.This dial is shown as rotated from a worm M3 on shaft lfl l driven inturn from a gear spiral l is on differential it). Indicator M2,therefore, shows the rudder position being actuated from the rudderfollow-up motor According to my present invention, l effect theadjustment known in the art as the weather adjustment in a differentmanner than hereto fore accomplished. This adjustment is for the purposeof varying the sensitivity of control so that in calm weather veryaccurate steering may be obtained while in rough weather over-warloingof the steering engine may be avoided by lessening the sensitivity ofthe device. According to my present invention I effect this purpose byvarying the normal speed of the motor instead of varying the play in alost motion ccnnection between the compass and controller as heretoforegenerally done. his has theadvantage that the sensitivity o control isnot because a deviation of its course which persists longer than thenormal period. of weather yaw will always cause a rudder response.

it is connected to one side or the A.

When the weather is bad and a non-sensitive control is desired therheostat R is placed on the slow speed contact 8. In this position, al-

though the counter E. M. F. in the motor is control is desired for fairweather steering, it is placed on contact F. In the latter position itwill be seen that that portion of the resistance in series with thearmature is reduced to a minimum, while that portion in shunt with thearma ture is increased to a. maximum. The use of the shunt resistancealso serves to steady the motor when operated on alternating current andimprove the starting torque, especially at low speed.

Inaccordance with the provisions of the patent statutes, 1 have hereindescribed the principle and operation of my invention, together with theapparatus which I now consider to represent the best embodiment thereof,but I desire to have it understood that the apparatus shown is onlyillustrative and that the invention can be carried out by other means.Also, while it is designed to use the various features and elements inthe combination and relations described, some of these may be alteredand others omitted without interfering with the more general resultsoutlined, and the invention extends to such use.

Having described my invention, what I claim and desire to secure byLetters Patent is: l. l'n'a self-synchronous receiver, the combinationwith a repeating deviceof coarse and line repeater motors, the former ofwhich is adapted to be driven from a coarse transmitter having aone-to-one drive with the sending instrument and the latter to be drivenfrom a fine transmitter having a multiple drive from said instru merit,a power motor for driving said device, a.

between said last-named contacts and the con c tact on the second of thefirst mentioned cams whereby said contacts are rendered inoperative whenthe receiver out of synchronis more than a predetermined angle, and acircu other wise normally completed for normally driving said powermotor in either direction as one or the other of said contacts isclosed.

in a self-synchronous power means for tuming a heavy object, areversible power motor, a contact device comprising a cam an a pair cz?reversing contacts operated thereby for normally operating said motor,an auxiliary con-- tact device driven at a :iractional speed of n deviceand at a one to one ratio with ohlect, comprising a pair of cam a contact on one surface iorbrealring the circuit to pair of contacts whenthe angle said surface and contact exceeds a predeter -ed value, a pairof reversing contacts on the other surface adapted to assume control ofsaid ill motor as said circuit is broken. and follow-back connectionsfrom said motor to said cams and contacts.

3. In an automatic steering device, the combination with the controllerand steering motor, of a follow-back connection between said motor andcontroller including a driving shaft, a driven shaft, and an adjustablelost motion connection between the same comprising asleeve forconnecting the ends of said shafts, said sleeve and shafts havingcooperating pins and triangularlyshaped slots for said pins, and meansfor ad- Justing said sleeve longitudinally along said shafts to vary theamount of lost motion.

4. In an automatic steering device, the combinatlon with the controllerand steering motor,

of a follow-back connection between said motor and controller includinga driving shaft, a driven shaft, and an adjustable lost motionconnection between the same comprising a sleeve for connecting the endsof said shafts, a pin on each of said shafts taking in atriangularly-shaped slot in said sleeve, and means for adjusting saidsleeve longitudinally along said shafts to vary the amount oflost'motion.

5. In an automatic steering device, a master compass actuatedcontroller, a relay. motor excited therefrom, relay contacts actuated bysaid motor, a main steering motor actuated from said contacts, and aweather actiustment for varying at will the speed at which said relaymotor is actuated from said controller.

6. In an automatic steering device, a master compass controller, a relaymotor excited therefrom, relay contacts actuated by said motor, a mainsteering motor actuated from said contacts,

and means for varying at will the speed at which.

said relay motor is actuated from said controller as a weatheradjustment including a resistance shunted across the armature but notthe series field thereof, and means for tapping one side of the lineinto variable points therein to vary the proportion thereof in serieswith and in shunt with said armature,

'7. In an automatic steering device, a master compass actuatedcontroller, a relay motor excited therefrom, a follow-back connectionfrom said motor to said controller including a lost motion device, relaycontacts actuated by said motor, a main steering motor actuated fromsaid contacts, and a weather adjustment for varying at will the speed atwhich said relay motor is actuated from said controller.

FREDERICK S. HODGMAN.

